I have recently bought a 99 volvo s80 without the turbo and the car drives great and everything. I recently got an oil change then out of no where the No oil pressure light came on for a second when I pressed the brakes then turned back off. I took it back to the place where i got the oil change and they checked the levels and said that it is full. I Notice that the light only comes on when the car get hot and when I press the brake and it only stays on for a second and then goes away until i brake again then goes away and I do not hear any noise coming from the engine at all and the car does not shake and the rpm are normal. At first I thought it was the o rings but then I read that if they where bad the dipstick would have foamy oil on it and I did not see any foam at all. what can be causing this any help would be greatly appreciated

 

When the light comes on is the idle lower than normal?

 

No I do not believe so it usually stays the same maybe it will do a little dip that I do not notice but it does not do a dramatic drop

 

Did the oil change place use a Volvo or Mann filter?
The oil filter might be to small if it is an aftermarket one.

 

no I think they used an aftermarket one because they had trouble removing the oil filter so i had to return the next day just in case they broke the plastic thing holding the filter up and since they did not break it they they did not use they part and filter that they got from volvo they used their own/aftermarket one. so if the filter is too small that could be causing the no oil pressure light to turn on?

 

Yes it can it would not be sealing properly.

 

Thank you very much I will try to get it changed and soon as possible and hopfully it will will go away.

 

If it does not then you might need to have the oil pan o-rings replaced.

 

I thought you only needed to change the o rings if you had foam on the dipstick though?

 

They do not always have foam on the dipstick when they are bad.

 

ok thank you very much

 

Your welcome.